The present invention is related to the selective propagation of information between each area in a network. More specifically, the present invention is related to the prevention of routing loops and route leaking policies between areas of a network.
The Asynchronous Transfer Mode (ATM) Forum has defined a specification called PNNI (Private Network-Network Interface or Private Node-Node Interface) [Private Network-Network Interface Specification v1.0, The ATM Forum, af-pnni-0055.000, March 1996, incorporated by reference herein] for routing connections in an ATM network. This protocol is designed to scale to very large networks using the concept of hierarchical routing.
Although PNNI addresses scalability of private networks, it does not sufficiently address building a global ATM network comprising several PNNI areas. (An example of such a network would be a network of several enterprise networks inter-connected by one or more public carrier networks. In this case, each enterprise network and each of the public networks would be an individual PNNI area.) Especially, PNNI does not address implementation of policies for route leaking, summarization and suppression at the edges that separate the individual areas.
The present invention is directed to an architecture called Split-Switch Hierarchy which allows multiple PNNI areas to be connected into a single physical network and allows implementation of policies for leaking, summarizing and suppressing routing information being propagated between individual PNNI areas.
The present invention pertains to a telecommunications system. The system comprises a first area. The system comprises a second area connected to the first area to form a single physical network for routing connections and in which there is selective propagation of information between each area in the network.
The present invention pertains to a split switch. The split switch comprises a first node adapted to be disposed in a first area. The split switch comprises a second node adapted to be disposed in a second area. The second node is in communication with the first node. The first node prevents information from propagating into the first area from the second area which was provided to the second area from the first area or arose from the first area.
The present invention pertains to a method for routing connections. The method comprises the steps of propagating information concerning a connection from a first area of a physical network to a second area of the physical area. Then there is the step of preventing the information from forming a routing loop back to the first area.